Exposure to short flashes of light at night could be used as an effective treatment for jet lag, according to US scientists.
Researchers believe that cells in the retina, which transmit light information to the centres in the brain responsible for controlling sleep cycles, are key to readjusting the body’s internal clock when travelling across timezones.
During the study, the team at Stanford University compared the effects of exposure to an hour of continuous light and an hour of strobe light on 39 volunteers while they slept in a laboratory.
They found that people who slept under the strobe light reported a two-hour delay in the onset of sleepiness the following night, while those who slept in continuous light reported a delay of just over 30 minutes.
The human body synchronises to a daily 24-hour pattern of daytime and night and falls into a cycle of wakefulness and tiredness according to these changing light conditions.
However, when a person moves across timezones this cycle becomes disturbed as the light conditions to which the body has grown accustomed change, often leading to tiredness and mood changes.
The retina and pigments in the eye are key to controlling cycles of activity throughout a day, responding to light even through closed eyelids during sleep.
Exposing the eyes to short flashes of light appears to be an effective way to fool the brain into thinking that the day is longer than it really is, shifting its internal clock and combatting the effects of jet lag.
Dr Jamie Zeitzer, who led the research, said that this discovery could lead to far more effective methods of tackling jet lag.
He commented: “This could be a new way of adjusting much more quickly to time changes than other methods in use today.
“We have found that most people can sleep through the flashing light just fine.”
The research was published in the Journal of Clinical Investigation.
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